1. Field of the Invention
The present invention relates to a semiconductor wafer, a semiconductor device and a method for manufacturing the same, a circuit board, and an electronic apparatus.
2. Description of Related Art
Surface-mounted packages are known to be semiconductor devices that satisfy requirements, such as mountability or greater packaging density. For example, in a chip scale/size package (CSP), wirings are disposed on a semiconductor chip with a resin layer interposed therebetween, and an external terminal (for example, a solder ball) is provided on the wirings. Thus, when the external terminal is provided on the wirings, it is required that the bonding strength and the electrical connectivity between them be improved.
It is an advantage of the present invention to improve the bonding strength and the electrical connectivity between the wirings and external terminals.
A semiconductor device according to the present invention includes a semiconductor chip provided with an integrated circuit and a pad that is electrically connected to the integrated circuit. A wiring layer has a concave portion and is electrically connected to the pad. An external terminal is joined to the concave portion of the wiring layer. A resin layer has a through hole and is disposed on the wiring layer. The through hole and the concave portion reside at the same position. According to the present invention, the bonding strength between the wiring layer and the external terminal increases because of the formation of the concave portion in the wiring layer. In addition, the formation of the concave portion results in a larger contact area between the wiring layer and the external terminal, and thereby the electrical connectivity between them is improved.
According to an embodiment of the present invention, the width of the concave portion may increase with depth, the concave portion may have a first width at a first depth and a second width at a second depth that is deeper than the first depth with the first width being larger than an opening size of the concave portion and the second width being smaller than the first width. The inner surface of the through hole in the resin layer may be in contact with the external terminal, and a stress relaxation layer is disposed on the semiconductor chip and the wiring layer may be disposed on the stress relaxation layer.
In the semiconductor device, the resin layer may be prepared from a solder resist. A circuit board according to the present invention includes the semiconductor device described above and an electronic apparatus according to the present invention includes the semiconductor device described above.
A semiconductor wafer according to an embodiment of the present invention includes a semiconductor substrate provided with a plurality of integrated circuits and pads each electrically connected to each of the integrated circuits. A wiring layer has a concave portion and is electrically connected to the pads. An external terminal is joined to the concave portion of the wiring layer. A resin layer has a through hole and is disposed on the wiring layer. The through hole and the concave portion reside at the same position. According to the present invention, the bonding strength between the wiring layer and the external terminal increases because of the formation of the concave portion in the wiring layer. In addition, the formation of the concave portion results in a larger contact area between the wiring layer and the external terminal, and thereby the electrical connectivity between them is improved. According to an embodiment of the present invention, the width of the concave portion may increase with depth and the concave portion may have a first width at a first depth and a second width at a second depth that is deeper than the first depth, the first width being larger than an opening size of the concave portion and the second width being smaller than the first width.
The inner surface of the through hole in the resin layer may be in contact with the external terminal, a stress relaxation layer is disposed on the semiconductor substrate and the wiring layer is disposed on the stress relaxation layer, and the resin layer may be prepared from a solder resist.
A method for manufacturing a semiconductor device includes forming a wiring layer over a semiconductor substrate provided with a integrated circuit and a pad that is electrically connected to the integrated circuit. The wiring layer is electrically connected to the pad. The method also includes forming a resin layer so as to cover the wiring layer, forming a through hole and a concave portion in the resin layer and the wiring layer respectively, the through hole and the concave portion residing at the same position, and providing an external terminal so as to be joined to the concave portion of the wiring layer. According to the present invention, the bonding strength between the wiring layer and the external terminal increases because the wiring layer has the concave portion in which the external terminal is placed. In addition, the formation of the concave portion results in a larger contact area between the wiring layer and the external terminal, and thereby the electrical connectivity between them is improved.
In a method for manufacturing the semiconductor device, the through hole may be formed in the resin layer and then the concave portion may be formed in the wiring layer.
Embodiments of the present invention will now be illustrated with reference to the drawings.